Heat example: boundary and solution
Boundary & Solution: u(x,y) = x on [0,1]?[0,1]
(uij)i=–1,...,m, j=–1,...,n =
u–1, –1 u–1, 0 ... u–1, n–1 u–1, n
u 0, –1 u 0, 0 ... u 0, n–1 u 0, n
um–1, –1 um–1, 0 ... um–1, n–1 um–1, n
um, –1 um, 0 ... um, n–1 um, n